This section is intended to provide background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.
Gate valves for controlling the flow of fluids typically include a slidable gate moveable between two positions. In the first position, a solid portion of the gate blocks the flow through the valve by intersecting the passageway of fluid flow. In the second position, the gate is raised so that it does not intersect the passageway and allows the flow of fluid through the valve.
The gate can be operated by a circular hand wheel or a hydraulic cylinder. The hand wheel or hydraulic cylinder can be coupled to a stem that adjusts the position of the gate. An inner end of the stem is connected with an end of the gate so that the linear movement of the stem into and out of the valve body carries with it the gate to control the flow of fluid through the valve.
The gate is positioned between two valve seats. A valve seat is generally a ring-shaped structure that has an interior passageway that corresponds in shape and size with the flow passageway through the valve. Typically, the valve seat includes a rectangular cross-section that interfaces with the valve body in a seat pocket.